Integrated Process Synthesis – designing processes for reduced CO2 emissions

The Cen­tre of Mate­ri­als and Process Syn­the­sis, Uni­ver­si­ty of the Wit­wa­ter­srand, South Africa, is pre­sent­ing a short course, “Inte­grat­ed Process Syn­the­sis – design­ing process­es for reduced CO2 emis­sions”, under the aus­pices of the AIChE in Orlan­do on 12–14 Novem­ber 2008. The approach pre­sent­ed in the course rep­re­sents the work of Pro­fes­sors David Glass­er and Diane Hilde­brandt, who are amongst the lead­ers in the field of process syn­the­sis.

For more infor­ma­tion, please vis­it COMPS

A Primer on Chemical Reactions and Catalysis

From Pref­ace of Basic Research Needs: Catal­y­sis for Ener­gy, 2008

Chem­i­cal trans­for­ma­tions are essen­tial to all liv­ing organisms—and also to the man­u­fac­ture of many prod­ucts includ­ing fuels, plas­tics, and phar­ma­ceu­ti­cals. With­out cat­a­lysts and cat­alyt­ic tech­nolo­gies, the ease of trans­porta­tion and the ready access to all of the mate­ri­als need­ed for our dai­ly lives would not be pos­si­ble. The pur­pose of this primer is to show why cat­a­lysts are required for bio­log­i­cal process­es as well as those used in tech­nol­o­gy for the pro­duc­tion of most fuels, chem­i­cals, poly­mers, and phar­ma­ceu­ti­cals. As we shall see, cat­a­lysts are the ulti­mate enablers of chem­i­cal trans­for­ma­tion.

Cat­a­lysts Facil­i­tate Mol­e­c­u­lar Trans­for­ma­tions

The extent to which a chem­i­cal reac­tion could pos­si­bly trans­form one kind of mol­e­cule into anoth­er kind of mol­e­cule is gov­erned by the prin­ci­ples of thermodynamics—some reac­tions are in prin­ci­ple pos­si­ble, where­as oth­ers can, at most, occur to only an immea­sur­ably small extent. But, the reac­tions that are ther­mo­dy­nam­i­cal­ly pos­si­ble may take place at such low rates as to be essen­tial­ly stymied—we say that these reac­tions are lim­it­ed by kinet­ics. When the reac­tion is ther­mo­dy­nam­i­cal­ly pos­si­ble but too slow to be use­ful, then a cat­a­lyst is need­ed. A cat­a­lyst increas­es the rate by inter­ven­ing in the chem­i­cal change to open up a new, quick­er path­way for change.

Ther­mo­dy­nam­ics and Chem­i­cal Reac­tions

Chem­i­cal reac­tions involve the trans­for­ma­tion of reac­tant mol­e­cules to prod­uct mol­e­cules. A sim­ple exam­ple is the com­bus­tion of hydro­car­bons such as gaso­line mol­e­cules to make car­bon diox­ide and water, a process that occurs at high tem­per­a­ture in the cylin­der of an auto­mo­bile engine. The Gibbs free ener­gy change for this reac­tion, assum­ing hexa­ne as a typ­i­cal fuel, is down­hill by ~ 68 MJ/L , and the ener­gy released does the work to dri­ve a typ­i­cal auto­mo­bile 12.5 miles. The fact that the free ener­gy change is down­hill tells us that the reac­tion is favor­able and that once it occurs, the prod­ucts have a low­er poten­tial for doing work than the reac­tants do. Process­es that are char­ac­ter­ized by such down­hill changes in the Gibbs free ener­gy can, in prin­ci­ple, occur spon­ta­neous­ly. The larg­er the mag­ni­tude of the change in the Gibbs free ener­gy, the larg­er the ulti­mate frac­tion of the reac­tants that can be con­vert­ed to prod­ucts. Though the change in Gibbs free ener­gy for hexa­ne com­bus­tion is large, the reac­tion does not occur spon­ta­neous­ly. Thus, one can place liq­uid hexa­ne in a glass and observe that it does not burst into flame when exposed to air at room tem­per­a­ture. The rea­son for the lack of com­bus­tion of hexa­ne is that the mol­e­cules of hexa­ne and oxy­gen are con­tent to stay as they are for a very long time. To react, chem­i­cal bonds in both kinds of mol­e­cules must first break before new ones can form. To get these bonds to break, the tem­per­a­ture of the hexa­ne-oxy­gen mix­ture is raised (as occurs in the auto­mo­bile cylin­der). The need for the high tem­per­a­ture is asso­ci­at­ed with a bar­ri­er along the path­way from reac­tant to prod­uct mol­e­cules, known as the acti­va­tion bar­ri­er. When the reac­tant mol­e­cules are hot, they have the ener­gy to cross the acti­va­tion bar­ri­er, as the bonds between atoms in the reac­tant mol­e­cule are bro­ken and the trans­for­ma­tion of reac­tants to prod­ucts ensues. The high­er the bar­ri­er, the slow­er the reac­tion.

Kinet­ic Ener­gy and Chem­i­cal Reac­tions

We empha­size that the rea­son reac­tions pro­ceed more rapid­ly at high­er tem­per­a­tures is asso­ci­at­ed with the high­er ener­gy of the reac­tant molecules—we call this “kinet­ic ener­gy.” A col­lec­tion of mol­e­cules has a dis­tri­b­u­tion of kinet­ic ener­gies, some high, some low, but the aver­age val­ue of kinet­ic ener­gy is deter­mined by the tem­per­a­ture. If a reac­tion is to occur, some frac­tion of the mol­e­cules in the col­lec­tion must have enough kinet­ic ener­gy to over­come the bar­ri­er. If we think of reac­tant mol­e­cules as skate­board­ers at the bot­tom of a trough, then to sur­mount the walls of the trough and move over to a new trough, some frac­tion of the skate­board­ers will need to be mov­ing fast enough (i.e., have suf­fi­cient kinet­ic ener­gy) to sur­mount the bar­ri­er. Thus, the high­er the tem­per­a­ture, the greater the frac­tion of the reac­tant mol­e­cules able to over­come the acti­va­tion bar­ri­er and move over to the prod­uct side of the land­scape. If the acti­va­tion bar­ri­er is very high, the tem­per­a­ture required to achieve a use­ful rate of prod­uct for­ma­tion will have to be so high that the ves­sel walls used to con­tain the reac­tion may fail—or the reac­tion could be so fast that it gets out of con­trol (an explo­sion could occur!). Alter­na­tive­ly, the cost of the ener­gy required to increase the tem­per­a­ture suf­fi­cient­ly for reac­tion to occur could become pro­hib­i­tive. Fur­ther­more, at high tem­per­a­tures, some reac­tants may be frag­ile enough that they will decom­pose to use­less prod­ucts. Thus, rais­ing the tem­per­a­ture need­ed to achieve a use­ful reac­tion rate can lead to var­i­ous prob­lems, and a bet­ter way is need­ed to get the reac­tants over the bar­ri­er to form prod­ucts.

Why Cat­a­lysts Mat­ter

Cat­a­lysts pro­vide the bet­ter way. They alter the path­way for the reac­tion, so that the bar­ri­er becomes small­er. The cat­a­lyst works by inter­act­ing with the reac­tant mol­e­cules (form­ing chem­i­cal bonds with them) to alter the ener­gy land­scape for the reac­tion, lead­ing to a low­er acti­va­tion bar­ri­er and, hence, a high­er rate of reac­tion.

Because nature has to do most of its bio­log­i­cal chem­istry at near- ambi­ent con­di­tions, it has evolved an enor­mous set of cat­a­lysts, most­ly enzymes, which are exquis­ite­ly tuned so that each one facil­i­tates a sin­gle chem­i­cal reac­tion for a sin­gle reac­tant. When a series of reac­tions is to be car­ried out as, for exam­ple, in the metab­o­lism of food, nature uses a dif­fer­ent enzyme for each step in the series, and all the enzymes work in the same medi­um at the same tem­per­a­ture. Cat­a­lysts are also used to accel­er­ate the chem­i­cal reac­tions used in the fuels and chem­i­cals indus­try, but these cat­a­lysts are more prim­i­tive than nature’s cat­a­lysts. Thus, for exam­ple, if we want­ed to reduce the tem­per­a­ture of hexa­ne com­bus­tion, we could expose a hexa­ne-oxy­gen mix­ture to a cat­a­lyst con­tain­ing very small par­ti­cles— nanoparticles—of the pre­cious met­al plat­inum. This same cat­a­lyst con­verts unburned gaso­line in auto­mo­bile exhaust con­vert­ers, min­i­miz­ing the pol­lu­tion it would oth­er­wise cause, and it simul­ta­ne­ous­ly con­verts tox­ic car­bon monox­ide and nitro­gen oxides in the exhaust to the non-tox­ic prod­ucts car­bon diox­ide and nitro­gen. Cat­a­lysts are also used to enhance the rate of a reac­tion to a pre­ferred prod­uct rel­a­tive to an unde­sired prod­uct. For exam­ple, sil­ver cat­alyzes the oxi­da­tion of eth­yl­ene to eth­yl­ene oxide, the pre­cur­sor to eth­yl­ene gly­col, which is used as antifreeze in auto­mo­biles or as one of the monomers for mak­ing poly­eth­yl­ene tereph­tha­late, the poly­mer used for mak­ing soft drink bot­tles. The beau­ty of a prop­er­ly tuned sil­ver cat­a­lyst is that it pro­motes the oxi­da­tion of eth­yl­ene to eth­yl­ene oxide rather than the com­bus­tion of eth­yl­ene to car­bon diox­ide and water. Thus, even though the ther­mo­dy­nam­i­cal­ly pre­ferred prod­ucts are car­bon diox­ide and water, sil­ver alters the reac­tion path­way so that more than 90 per­cent of the eth­yl­ene goes to eth­yl­ene oxide. The net effect is that eth­yl­ene is used effi­cient­ly to make the valu­able prod­uct eth­yl­ene oxide and the unde­sired prod­ucts, car­bon diox­ide and water, are min­i­mized.

Dri­ving Chem­i­cal Reac­tions that are Ther­mo­dy­nam­i­cal­ly Uphill

Some reac­tions are char­ac­ter­ized by a change in the Gibbs free ener­gy of reac­tion that is uphill. For such reac­tions, ther­mo­dy­nam­ics teach­es us that the reac­tion can­not occur to a sig­nif­i­cant extent, unless ener­gy is sup­plied in the form of pho­tons (e.g., sun­light) or elec­trons (e.g., from a hydro­elec­tric gen­er­a­tor). For exam­ple, plants are able to dri­ve an uphill reac­tion con­vert­ing car­bon diox­ide and water to the sug­ar glu­cose and oxy­gen by using sun­light via the process of pho­to­syn­the­sis. Alter­na­tive­ly, the same reac­tants can be con­vert­ed elec­tro­chem­i­cal­ly into car­bon monox­ide and hydro­gen, a mix­ture that can be used with well-devel­oped cat­alyt­ic tech­nol­o­gy to man­u­fac­ture diesel fuel. The kinet­ics of reac­tions that are uphill ther­mo­dy­nam­i­cal­ly are often slow, even in the pres­ence of light or elec­trons. But, the inter­ven­tion of a cat­a­lyst opens a path­way for such reac­tions to occur at a high­er rate with low­er ener­gy require­ments for the pho­tons or elec­trons. Cat­a­lysts of this type are referred to as pho­to- or elec­tro­cat­a­lysts. Thus, for exam­ple, nature uses a series of enzymes to cat­alyze the pho­to­syn­the­sis of sug­ars from car­bon diox­ide and water, and plat­inum elec­trodes cat­alyze the con­ver­sion of the same reac­tants to car­bon monox­ide and hydro­gen.

In Sum­ma­ry

Cat­a­lysts are required to facil­i­tate chem­i­cal reac­tions so that they occur at use­ful rates and with pref­er­ence to the desired prod­uct. If the rate of a reac­tion is too low, the size of the ves­sel in which the reac­tion takes place will be exces­sive­ly large and expen­sive. If the prod­uct selec­tiv­i­ty is low, the reac­tants are not used effi­cient­ly, and ener­gy will be need­ed to sep­a­rate the desired prod­ucts from the unde­sired prod­ucts. Thus, the avail­abil­i­ty of cat­a­lysts that make the reac­tion go fast (active cat­a­lysts); make the reac­tion go to the desired prod­ucts (selec­tive cat­a­lysts); and last a long time or regen­er­ate them­selves (sta­ble or regen­er­a­ble cat­a­lysts) allows us to car­ry out chem­i­cal reac­tions in the most effi­cient, eco­nom­i­cal, and envi­ron­men­tal­ly respon­si­ble man­ner. More­over, using cat­a­lysts to reduce the tem­per­a­ture at which reac­tions occur while achiev­ing high con­ver­sions of reac­tants and high yields of desired prod­ucts allows us to car­ry out the trans­for­ma­tion with a max­i­mum sav­ings of the ener­gy con­sumed. Vir­tu­al­ly all of the prod­ucts used by mod­ern soci­eties for fuels, chem­i­cals, poly­mers, and phar­ma­ceu­ti­cals, as well as for abate­ment of air and water pol­lu­tion, depend on cat­a­lysts. It is notable that the cat­a­lysts dis­cov­ered and devel­oped by humankind are quite prim­i­tive rel­a­tive to those that nature has evolved. How­ev­er, advances made in the under­stand­ing of how cat­a­lysts work, togeth­er with advances in strate­gies for mak­ing them and the lessons learned from nature, are open­ing the way towards the design, prepa­ra­tion, and imple­men­ta­tion of cat­a­lysts that will rival nature’s own and spare our pre­cious ener­gy and raw mate­ri­als.

Catalysis in the Processing of Crude Oil

The refin­ing of crude oil into petro­le­um prod­ucts such as gaso­line (tril­lions of bar­rels) and oth­er chem­i­cals (bil­lions of pounds) is a major busi­ness that relies heav­i­ly on catal­y­sis. The petro­le­um refin­ing cat­a­lyst busi­ness is in excess of $650 mil­lion in the U.S. and over $ 1 bil­lion worldwide.@ Over 90% of our chem­i­cal prod­ucts are derived from petro­le­um. Once the crude oil is dis­tilled, the prod­ucts must be fur­ther treat­ed with cat­a­lysts to pro­duce valu­able prod­ucts. A major oper­a­tion with­in refiner­ies is cat­alyt­ic crack­ing. Crack­ing is the pro­duc­tion of small­er mol­e­cules, often for use in gaso­line pro­duc­tion, from the larg­er mol­e­cules dis­tilled from crude oil. Over 380 mil­lion pounds of cat­a­lyst* are used for this oper­a­tion every year. Oth­er major steps in the refin­ing of petro­le­um include hydrotreat­ing (a major cat­alyt­ic process used to remove unwant­ed sul­fur and amine con­tain­ing prod­ucts with­in petro­le­um), reform­ing (the use of plat­inum based cat­a­lysts for rear­rang­ing petro­le­um prod­ucts into gaso­line), and alky­la­tion (the use of large amounts of hydro­flu­o­ric or sul­fu­ric acids to obtain branched chain mol­e­cules with high­er octane num­bers). Alky­la­tion cat­a­lyst pro­duc­tion exceeds 200 mil­lion pounds, worldwide.@ Beyond the vol­ume and val­ue of the cat­a­lysts them­selves, there is a hugh val­ue-added com­po­nent obtained from the con­sumer prod­ucts derived from petro­le­um based by-prod­ucts.

Cat­a­lysts play an impor­tant eco­nom­ic role in extract­ing valu­able prod­ucts from petro­le­um effi­cient­ly. In the years to come, they will be a key part in devel­op­ing new fuels to meet tougher emis­sion con­trol require­ments and increas­ing our Nation’s ener­gy effi­cien­cy.

16 Sep­tem­ber, 1992, J.N. Armor

Mobile Engine Emission Control Catalysts

4 June 1994

Since the 1960s. the U. S. Gov­ern­ment (and now many oth­er coun­tries) required auto­mo­bile man­u­fac­tur­ers con­trol the emis­sion of nitro­gen oxides (NOx), car­bon monox­ide (CO), and hydro­car­bons pro­duced by gaso­line pow­ered auto­mo­biles. Emis­sions reg­u­la­tions estab­lished for 1982 and lat­er vehi­cles led to the devel­op­ment of the cur­rent three-way cat­a­lyst that simul­ta­ne­ous­ly con­trols all three pol­lu­tants to the required lev­els. In the late 1980s, this was already a $500 million/year busi­ness in the U. S.*

Typ­i­cal three way cat­a­lysts con­tain rhodi­um, plat­inum, and/or pal­la­di­um met­als with oth­er addi­tives that are all sup­port­ed on an alu­mi­na sup­port.# Gen­er­al­ly, the sup­port­ed cat­a­lyst is dis­trib­uted onto a ceram­ic hon­ey­comb that is then encased with­in a steel con­tain­er mount­ed under the pas­sen­ger com­part­ment. Exhaust gas­es then dif­fuse into the pores and react with a cat­a­lyst and exit as non-pol­lu­tants. The cat­a­lyst reduces the pol­lu­tants with­in about 0.5 sec­ond and oper­ates at about 1000°F. These durable sys­tems oper­ate effi­cient­ly for the life of the vehi­cle. Nev­er­the­less, new changes to the reg­u­la­tions will demand fur­ther cat­a­lyst improve­ments. Improved cat­a­lysts are need­ed for con­trol­ling cold start emis­sions from lean fuel oper­at­ed engines. Recent­ly, B. J. Coop­er summarized@ some of the tech­ni­cal chal­lenges remain­ing in auto-emis­sion con­trol catal­y­sis. Also, cat­a­lysts are need­ed for con­trol­ling emis­sions from diesel engines, espe­cial­ly with regard to soot con­trol.

John N. Armor, PhD
Group Head
Catal­y­sis Skill Cen­ter

* B. F. Greek, Chem­i­cal & Engi­neer­ing News, (May 29, 1989) 29–56.
# K. C. Tay­lor, Chemtech, (Sep­tem­ber 1990) 551–555.
@ B. J. Coop­er, Plat. Met. Rev. 38 (1994) 2–10.

Fluid Catalytic Cracking and Eger Murphree

Patent No. 2,451,804 Method of and Appa­ra­tus for Con­tact­ing Solids and Gas­es

Over half the world’s gaso­line is cur­rent­ly pro­duced by a process devel­oped in 1942 by a group called the “Four Horse­men” of Exxon Research and Engi­neer­ing Com­pa­ny. The world’s first com­mer­cial Flu­id Cat­alyt­ic Crack­ing facil­i­ty began pro­duc­tion for Exxon on May 25, 1942. The Flu­id Cat Crack­ing process rev­o­lu­tion­ized the petro­le­um indus­try by more effi­cient­ly trans­form­ing high­er boil­ing oils into lighter, usable prod­ucts.

The four Exxon inven­tors respon­si­ble for this crack­ing process are Don­ald L. Camp­bell, Homer Z. Mar­tin, Eger V. Mur­phree, and Charles Wes­ley Tyson.

When Exxon’s first com­mer­cial cat crack­ing facil­i­ty went on-line in 1942, the U.S. had just entered World War II and was fac­ing a short­age of high-octane avi­a­tion gaso­line. This new process allowed the U.S. petro­le­um indus­try to increase out­put of avi­a­tion fuel by 6,000% over the next three years. Flu­id Cat Crack­ing also aid­ed the rapid buildup of buta­di­ene pro­duc­tion, which enhanced Exxon’s process for mak­ing syn­thet­ic butyl rubber–another new tech­nol­o­gy vital to the Allied war effort.

In the 1930s, Exxon began look­ing for a way to increase the yield of high-octane gaso­line from crude oil. Researchers dis­cov­ered that a fine­ly pow­dered cat­a­lyst behaved like a flu­id when mixed with oil in the form of vapor. Dur­ing the crack­ing process, a cat­a­lyst will split hydro­car­bon mol­e­cule chains into small­er pieces. These small­er, or cracked, mol­e­cules then go through a dis­til­la­tion process to retrieve the usable prod­uct. Dur­ing the crack­ing process, the cat­a­lyst becomes cov­ered with car­bon; the car­bon is then burned off and the cat­a­lyst can be re-used.

Camp­bell, Mar­tin, Mur­phree, and Tyson began think­ing of a design that would allow for a mov­ing cat­a­lyst to ensure a steady and con­tin­u­ous crack­ing oper­a­tion. The four ulti­mate­ly invent­ed a flu­idized solids reac­tor bed and a pipe trans­fer sys­tem between the reac­tor and the regen­er­a­tor unit in which the cat­a­lyst is processed for re-use. In this way, the solids and gas­es are con­tin­u­ous­ly brought in con­tact with each oth­er to bring on the chem­i­cal change.

This work cul­mi­nat­ed in a 100 bar­rel-per-day demon­stra­tion pilot plant locat­ed at Exxon’s Baton Rouge facil­i­ty. The first com­mer­cial pro­duc­tion plant processed 13,000 bar­rels of heavy oil dai­ly, mak­ing 275,000 gal­lons of gaso­line.

Con­sid­ered essen­tial to refin­ery oper­a­tion, Flu­id Cat Crack­ing pro­duces gaso­line as well as heat­ing oil, fuel oil, propane, butane, and chem­i­cal feed­stocks that are instru­men­tal in pro­duc­ing oth­er prod­ucts such as plas­tics, syn­thet­ic rub­bers and fab­rics, and cos­met­ics. Dur­ing today’s Flu­id Cat Crack­ing process, a box­car load of cat­a­lyst is mixed with a stream of oil vapor every minute. It is this mix­ture, behav­ing like a flu­id, that moves con­tin­u­ous­ly through the sys­tem as crack­ing reac­tions take place.

Flu­id Cat Crack­ing cur­rent­ly takes place in over 370 Flu­id Cat Crack­ing units in refiner­ies around the world, pro­duc­ing almost 1/2 bil­lion gal­lons of gaso­line dai­ly. It is con­sid­ered one of the most impor­tant chem­i­cal engi­neer­ing achieve­ments of the 20th cen­tu­ry. Flu­id Cat Crack­ing tech­nol­o­gy con­tin­ues to evolve as clean­er high-per­for­mance fuels are explored.

Don­ald L. Camp­bell was born August 5, 1904 in Clin­ton, Iowa. He has always been fas­ci­nat­ed by invent­ing and solv­ing prob­lems. He first attend­ed Iowa State Uni­ver­si­ty, then MIT and the Har­vard Busi­ness School. Dur­ing his 41 years at Exxon, 25 were spent in Exxon Research & Engi­neer­ing. At his retire­ment in 1969, he held 30 patents and was the assis­tant to the vice pres­i­dent of New Areas of Research.

Homer Zettler Mar­tin was born on Novem­ber 20, 1910 in Chica­go, Illi­nois. He received his B.S. in chem­i­cal engi­neer­ing from the Illi­nois Insti­tute of Tech­nol­o­gy and his M.S. and Ph.D. from Michi­gan. After join­ing Exxon in 1937, he became one of its most pro­lif­ic inven­tors, with 82 patents upon his retire­ment in 1973. Mar­tin died in Sun City, Ari­zona on Sep­tem­ber 1, 1993.

Eger Vaugh­an Mur­phree, born Novem­ber 3, 1898 in Bay­onne, New Jer­sey, moved as a young­ster with his fam­i­ly to Ken­tucky. At Ken­tucky Uni­ver­si­ty, he grad­u­at­ed with degrees in chem­istry and math­e­mat­ics (1920), then went on for his mas­ter’s in chem­istry (1921). After work­ing as a high school teacher and foot­ball coach for a peri­od of time, he attend­ed MIT for two years. In 1924, he went to work at Solvay Process Com­pa­ny as a chem­i­cal engi­neer, and in 1930, joined what was then Stan­dard Oil of New Jer­sey. From 1947 to 1962, he served as pres­i­dent of the Stan­dard Oil Devel­op­ment Co., which was renamed Esso Research & Engi­neer­ing in 1955. In 1956, he was giv­en the job of direct­ing mil­i­tary projects relat­ed to the guid­ed-mis­sile pro­gram; he served one year as spe­cial assis­tant to Defense Sec­re­tary Charles Wil­son. Mur­phree, who was also a mem­ber of the com­mit­tee that orga­nized the Man­hat­tan Project, was wide­ly rec­og­nized as a leader in the fields of syn­thet­ic toluene, buta­di­ene and hydro­car­bon syn­the­sis, flu­id cat­alyt­ic crack­ing, flu­id hydro­form­ing, and flu­id cok­ing. He died of a heart attack in 1962.

Charles Wes­ley Tyson, known as Wes to his friends, was born in 1900. In 1930, after receiv­ing his bach­e­lor’s and mas­ter’s degrees in chem­i­cal engi­neer­ing from MIT, he joined Esso. In 1961, he was appoint­ed spe­cial assis­tant to the vice pres­i­dent of Exxon Research & Engi­neer­ing, and at his retire­ment in 1962, he held 50 patents. Tyson died in 1977.

Copy­right 1999, Nation­al Inven­tors Hall of Fame, Akron, Ohio.

About Catalysis

Cat­a­lysts, in the def­i­n­i­tion devel­oped by Berzelius and oth­ers in the last cen­tu­ry, are mate­ri­als which change the rate of attain­ment of chem­i­cal equi­lib­ri­um with­out them­selves being changed or con­sumed in the process.

Catal­y­sis is an aston­ish­ing phe­nom­e­non. Some cat­a­lysts achieve aston­ish­ing activ­i­ties, so that very small quan­ti­ties of cat­a­lyst can con­vert thou­sands or mil­lions of times their own weight of chem­i­cals. Equal­ly sig­nif­i­cant, how­ev­er, is selec­tiv­i­ty; usu­al­ly thought of in terms of a cat­a­lyst accel­er­at­ing one of a num­ber of com­pet­ing reac­tions, but also pos­si­ble by virtue of a cat­a­lyst select­ing one reagent out of a com­plex mix­ture.

Catal­y­sis is the key to both life and lifestyle. It is an essen­tial tech­nol­o­gy for chem­i­cal and mate­ri­als man­u­fac­tur­ing, for fuel cells and oth­er ener­gy con­ver­sion sys­tems, for com­bus­tion devices, and for pol­lu­tion con­trol sys­tems. Cat­a­lysts are wide­ly used in food pro­cess­ing, and enhance the per­for­mance of oth­er con­sumer prod­ucts such as laun­dry deter­gents. The pos­si­bil­i­ty of analysing and ulti­mate­ly manip­u­lat­ing genes rests on the cat­alyt­ic prop­er­ties of RNA to repli­cate mol­e­cules con­tain­ing bio­log­i­cal infor­ma­tion. New sen­sor sys­tems use cat­alyt­ic sur­faces to detect spe­cif­ic mol­e­cules and announce their pres­ence through the heat of a vig­or­ous cat­alyt­ic reac­tion. And while the ten­den­cy is to think of catal­y­sis as a phe­nom­e­non for mak­ing things hap­pen, the basis of many valu­able drugs is the oppo­site phe­nom­e­non; Via­gra and Quinapril com­bat impo­tence and hyper­ten­sion by inhibit­ing enzymes, respec­tive­ly PDE‑V, a phos­pho­di­esterase which breaks down the NO mes­sen­ger cGMP, and ACE, the Angiotensin-Con­vert­ing Enzyme.

The eco­nom­ic con­tri­bu­tion from catal­y­sis is as remark­able as the phe­nom­e­non itself. Esti­mates from just four years ago that 35% of glob­al GDP depends on catal­y­sis missed much of the emer­gent genet­ic busi­ness. Con­fin­ing the analy­sis to the chem­i­cals indus­try, with glob­al sales of per­haps US$1.5 x 1012 the pro­por­tion of process­es using cat­a­lysts is 80% and increas­ing. The cat­a­lyst mar­ket itself is US$1010, so that catal­y­sis costs are much less than 1% of the sales rev­enue from the prod­ucts which they help cre­ate. Small won­der that the cat­a­lyst mar­ket is increas­ing at 5% per annum.

The terms “cat­a­lyst” and “catal­y­sis” have also trans­lat­ed from the world of sci­ence to every­day cliché. Our west­ern soci­ety places a high val­ue on the pow­er to induce change, under the descrip­tor “progress”, and it is small won­der that “cat­a­lyst” is a trade­name cho­sen for wine, per­fume, mag­a­zines, man­age­ment con­sul­tan­cies and adver­tis­ing agen­cies. There is even a breed of com­ic-book super­heroes.

The east­ern tra­di­tion is dif­fer­ent. Rather than depict­ing a cat­a­lyst as an agent of rapid break­down and change, the Chi­nese char­ac­ters for “cat­a­lyst” also apply to “mar­riage bro­ker”.

This is a sub­tle and per­cep­tive appre­ci­a­tion of how cat­a­lysts work. It also seems most appro­pri­ate giv­en that the suc­cess­ful cre­ation and appli­ca­tion of cat­alyt­ic process­es is gen­uine­ly mul­ti­dis­ci­pli­nary. On a tech­ni­cal lev­el it requires skills in chem­istry, chem­i­cal engi­neer­ing, mate­ri­als tech­nol­o­gy, as well as the eco­nom­ics and prac­ti­cal­i­ties of man­u­fac­tur­ing process­es. And it can best be induced by active and strate­gic col­lab­o­ra­tion between indus­try, uni­ver­si­ties and gov­ern­ment.

Chris Adams
Insti­tute of Applied Catal­y­sis
See also: “Catalysing Busi­ness” by C J Adams, Chem­istry and Indus­try, 1999, pp740-743